From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jeff Kirsher Subject: [net-next 12/13] i40e/i40evf: carefully fill tx ring Date: Wed, 5 Mar 2014 20:21:43 -0800 Message-ID: <1394079704-1108-13-git-send-email-jeffrey.t.kirsher@intel.com> References: <1394079704-1108-1-git-send-email-jeffrey.t.kirsher@intel.com> Cc: Jesse Brandeburg , netdev@vger.kernel.org, gospo@redhat.com, sassmann@redhat.com, Catherine Sullivan , Jeff Kirsher To: davem@davemloft.net Return-path: Received: from mga02.intel.com ([134.134.136.20]:55320 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753314AbaCFEV4 (ORCPT ); Wed, 5 Mar 2014 23:21:56 -0500 In-Reply-To: <1394079704-1108-1-git-send-email-jeffrey.t.kirsher@intel.com> Sender: netdev-owner@vger.kernel.org List-ID: From: Jesse Brandeburg We need to make sure that we stay away from the cache line where the DD bit (done) may be getting written back for the transmit ring since the hardware may be writing the whole cache line for a partial update. Change-ID: Id0b6dfc01f654def6a2a021af185803be1915d7e Signed-off-by: Jesse Brandeburg Signed-off-by: Catherine Sullivan Tested-by: Kavindya Deegala Signed-off-by: Jeff Kirsher --- drivers/net/ethernet/intel/i40e/i40e_txrx.c | 4 ++-- drivers/net/ethernet/intel/i40evf/i40e_txrx.c | 4 ++-- 2 files changed, 4 insertions(+), 4 deletions(-) diff --git a/drivers/net/ethernet/intel/i40e/i40e_txrx.c b/drivers/net/ethernet/intel/i40e/i40e_txrx.c index e4497f8..2081bdb 100644 --- a/drivers/net/ethernet/intel/i40e/i40e_txrx.c +++ b/drivers/net/ethernet/intel/i40e/i40e_txrx.c @@ -2102,7 +2102,7 @@ static int i40e_xmit_descriptor_count(struct sk_buff *skb, /* need: 1 descriptor per page * PAGE_SIZE/I40E_MAX_DATA_PER_TXD, * + 1 desc for skb_head_len/I40E_MAX_DATA_PER_TXD, - * + 2 desc gap to keep tail from touching head, + * + 4 desc gap to avoid the cache line where head is, * + 1 desc for context descriptor, * otherwise try next time */ @@ -2113,7 +2113,7 @@ static int i40e_xmit_descriptor_count(struct sk_buff *skb, count += skb_shinfo(skb)->nr_frags; #endif count += TXD_USE_COUNT(skb_headlen(skb)); - if (i40e_maybe_stop_tx(tx_ring, count + 3)) { + if (i40e_maybe_stop_tx(tx_ring, count + 4 + 1)) { tx_ring->tx_stats.tx_busy++; return 0; } diff --git a/drivers/net/ethernet/intel/i40evf/i40e_txrx.c b/drivers/net/ethernet/intel/i40evf/i40e_txrx.c index 01bfab7..b1d87c6 100644 --- a/drivers/net/ethernet/intel/i40evf/i40e_txrx.c +++ b/drivers/net/ethernet/intel/i40evf/i40e_txrx.c @@ -1482,7 +1482,7 @@ static int i40e_xmit_descriptor_count(struct sk_buff *skb, /* need: 1 descriptor per page * PAGE_SIZE/I40E_MAX_DATA_PER_TXD, * + 1 desc for skb_head_len/I40E_MAX_DATA_PER_TXD, - * + 2 desc gap to keep tail from touching head, + * + 4 desc gap to avoid the cache line where head is, * + 1 desc for context descriptor, * otherwise try next time */ @@ -1493,7 +1493,7 @@ static int i40e_xmit_descriptor_count(struct sk_buff *skb, count += skb_shinfo(skb)->nr_frags; #endif count += TXD_USE_COUNT(skb_headlen(skb)); - if (i40e_maybe_stop_tx(tx_ring, count + 3)) { + if (i40e_maybe_stop_tx(tx_ring, count + 4 + 1)) { tx_ring->tx_stats.tx_busy++; return 0; } -- 1.8.3.1